When you're looking for a good silicone sealant to keep around for odd jobs, Gorilla Waterproof Caulk & Seal is our top pick. It seals out water, air and moisture for a mildew-free finish.

Other essential items include a caulking gun ... Unlike other sealants, silicone stays rubbery and is waterproof, so it can handle the constant expansions and contractions that come with moisture ...